Go! -- a division of Phoenix-based Mesa Air Group -- responded by doubling the number of $1 fares to 2,000 and extending the 12-hour deadline another five hours until midnight, or until all $1 fares were gone.

Hawaiian Airlines and Aloha Airlines declined to match.

Go! said the shutdown occurred because its booking-engine provider, Sabre, had not supplied enough capacity to meet demand. The go! site generated 20,000 independent hits in the first hour.

It was a no-go for about eight hours yesterday as frustrated airline passengers tried to take advantage of 1,000 promotional $1 one-way tickets offered by interisland carrier go!

Heavy volume triggered a server crash at go!'s Internet booking-engine provider, Sabre, resulting in all but a few passengers being shut out of the fares, offered in conjunction with go!'s one-year anniversary.

The go! Web site, www.iflygo.com, received 20,000 independent hits during the first hour and the go! office was flooded with calls and e-mails "all day," a go! spokesman said.

But shortly before 3 p.m., the reservation site began functioning again, and would-be passengers were able to snap up $1 tickets, the number of which the company increased to 2,000 later in the day in light of the inconvenience. The 12-hour deadline for purchasing $1 tickets, which were predominantly for travel on Tuesday, Wednesday and Thursday, also was extended to midnight last night -- or until a sell-out -- from the original 7 p.m. deadline.

"The problem is that Sabre was not prepared," Jonathan Ornstein, chairman and chief executive of go! parent Mesa Air Group, said earlier in the day about the shutdown. "The Sabre system effectively crashed with all the interest. It's not that people aren't getting the sale and it's slow; it's just down. While we're delighted with the demand, we're not very happy with our vendor and apologize for the inconvenience to people."

Hawaiian declined to comment on the promotion but Aloha went on the offensive.

"After a year of trying, this is clearly an act of a desperate airline," Aloha spokesman Stu Glauberman said. "We believe that the people of Hawaii will recognize this for what it is and stay loyal to their homegrown carriers."

Ornstein scoffed at Aloha's remarks.

"If this is desperate, I'd love to be as desperate as Ryanair, which sells 20 percent of its seats for free and is the most successful airline in the world," he said. "You've got old, stodgy managements that don't know how to react to a more vibrant and more creative approach. The people in Hawaii have not forgotten the days of the $100 fares before we got here and asking for loyalty now rings hollow."

Aloha has alleged in a lawsuit against Mesa that the Phoenix-based carrier is offering unrealistic fares to drive Aloha out of business. Aloha also alleged that Mesa has used proprietary information obtained as a potential bidder during Aloha's bankruptcy. Hawaiian has alleged the same proprietary violation in a separate lawsuit against Mesa.

The last time a marketing move of this magnitude occurred in the local airline market was last June, when Aloha gave away 1,000 free round-trip tickets rather than match go!'s $19 fare at the time. That promotion attracted 1,600 people who waited in line at the state's various airports.

"Aloha speaks with a forked tongue," Ornstein said. "On one hand, when they do it, it's a good thing. When we do it, it's a sign of desperation. The only difference is we didn't make people wait in line at the airport."

Joe Bock, chief marketing officer for go!, said the crash of the reservation system was attributable to GetThere, a brand of Sabre that handles go!'s reservation system. Though go!'s home page was accessible during the meltdown, users attempting to book a flight received various error messages that indicated the system was down. Eventually, GetThere added more capacity to go!'s connection.

"We got about 100 e-mails and people calling wanting to know what happened," Ornstein said. "We responded to all of them within minutes and I actually spoke to some customers today and everybody understood we had a technology glitch. This was not clearly our preferred course, but we just had to deal with it and we did it as quickly as we could."

Separately, go! announced yesterday that it filled 63.3 percent of its seats in May, up from 62.8 percent the previous month. The so-called load factor for go! has remained in the low 60 percent range during the last four months. The 57,935 passengers in May represented go!'s highest number in 2007.